Macro with TTartisans 40mm F2.8 and Extension tubes- has anyone tried before?

MacM545 wrote:

gardenersassistant wrote:

MacM545 wrote:

Eggplantt wrote:

Maybe consider combining the extension tubes with a quality close up lens?

Seeing as how you've reversed some non-macro lenses, I don't think a perfectly flat field is what you need (but my experience with close up lenses can reveal very good performance across 2/3rds of the frame at f5.6 on 50mm lenses).

And a close up lens will allow to work at a higher effective aperture, which is important.

That's a great idea. but in practice, I've not found it practical from what I remember. I've tried extension with a close up lens by Nisi for about $75 on a 320mm lens. It was surprising to me, because any existent loss of image quality wasn't noticeable to me with the close-up lens. also, the extension tubes together didn't seem to cause, for me, a noticeable lack of image quality. It was the Fuji 50-230mm 2nd version.

The extension tubes definitely worked on the 23mm Viltrox, but by the time the focus was about 1mm away from the lens, the magnification despite the close focus was only 0.4X. For the close-up lens to work to achieve 2X, it would require a focal length of ~400mm or more.

With a Raynox 250 on a 55-250 lens at 250mm on a Canon 70D I get a tiny fraction less that 2:1 (11.5mm scene width with a 22.5mm sensor width), with a working distance of around 115mm.

The close-up is in a way the opposite of extension tubes. An extension tube works more effectively for a wider angle lens, but a close-up lens is more effective for a longer focal length.

True.

That being said, it might work differently with an SLR.

I don't think it is different with a dSLR.

I've been wanting a Raynox 250, but was trying to figure how I'd mount the thing to a 52mm and 49mm lens. Not saying that it's not possible, but probably simply haven't found the exact accessory that I might need.

The Raynox 250, like the Raynox 150, comes with a spring-loaded adapter. This can be clipped on to any 52mm to 67mm filter thread. For 49mm, you can use a 49mm to 52mm step up ring (or a 49 to anything up to 67) and use the adapter.

Alternatively you can use the Raynox 250 (like the Raynox 150) without using the adapter. They have a 43mm thread so you can use step ring(s) to get from 49 to 43 and/or 52 to 43.

seems pretty good for a 250mm lens!

That is 250mm used on a Canon 1.6X crop factor camera. With a different crop factor the scene size covered will be different.

The reverse lens technique can work differently to some extent for an SLR. It could be that extension tubes and close up lens might be working the same as for mirrorless. If I can somehow find how to do with a Raynox, I might finally make it work. BTW, is the 250 the strongest close up lens?

No, there are stronger ones. The strength is measured in diopters, the higher the diopter value the strong the close-up lens.

The focal length of a close-up lens is 1000 / diopters mm. So for example the Raynox 250 is 8 diopters, so its focal length is 1000 / 8 mm = 125mm. That is the working distance, between the lens and the subject when the camera lens is focused at infinity. If the working distance is more than this you cannot gain focus. The working distance can be less than this - how much less depends on the camera lens on which the Raynox is mounted.

The Raynox 150 is 4.8 diopters. The Raynox 250 is 8 diopters. The Raynox 202 is 25 diopters. The Raynox 505 is 32 diopters. These last two are the strongest close-up lenses I know of. They have very short working distances.

To get a sharp image you need to have the working distance between the maximum and minimum working distance. How wide that is depends on how close the camera lens can focus.

As the power of the close-up lenses goes up, the difference between the maximum and minimum working distance gets smaller. For the Raynox 202 and even more so for the Raynox 505, the difference approaches zero, so you have to be at exactly the right working distance. If you are using manual focus that is not a problem, because whatever kit one is using one typically fine tunes the focus by moving the camera back and forth a little. However, if you want to use autofocus the Raynox 202 and even more so the Raynox 505 can be quite tricky to use out in the field, because autofocus will only engage when you are within the acceptable range of working distance. (I found autofocus worked quite well most of the time with the Raynox 150 and 250, which were the close-up lenses I used most, although how well autofocus works, and indeed whether it works at all, depends on the camera+lens setup. In my case it was better on my Panasonic fixed lens small sensor bridge cameras and micro four thirds cameras than with my Canon APS-C setup. With the first 55-250 lens I got with the Canon autofocus didn't work very well with the Raynox 150 and hardly at all with the Raynox 250. When I swapped that 55-250 for a later model autofocus worked ok with both of them, although not quite as fast or accurate as with the Panasonic setups.)

Rather than using a Raynox 202 or 505, you can get greater magnification than with the Raynox 250 by adding a Raynox 150 (to give a total of 8 + 4.8 = 12.8 diopters, or a second Raynox 250 to give a total of 8 + 8 = 16 diopters. These combinations are a bit easier to use than the more powerful 202 and 505.